Cat Whisperer: I'm not so certain I would trust the Destroyer Carbine with a 38 Super. I know that you need to open the bolt face, minutely, to get that semi-rimmed round to feed, but with the availability of surplus 9mm Largo and 9x23 brass, I would stay closer to the 9mm Largo loadings than try and go heavier with the 38 Super.
Years ago you could find Astra 400s that would accept the 38 Super, and the Star Modelo B in 9mm Largo would do the same, but we always wound up breaking irreplaceable parts using the hotter loads. Just about the only european handgun that would safely handle the 38 Supers, at that time, was the Llama, specifically chambered for the 38 Super. These were identified on the slide as 38 Super/9mm Largo, or 38/9mm, indicating the interchangeability of the round.
I like my little Destroyer Carbine. Using older surplus ammo I don't get much in the way of groups at 25 yds (3-4") but using some of the newer CCI aluminum cased ammo, she groups better (2"). I've toyed with a few handloads but have found she doesn't shoot much, or any, better with cast bullets than the jacketted. I think the twist in those barrel is a 1:10 9mm twist that favors jacketted bullets. A buncha years ago I got a 9mm Luger or 9x19 chamber adapter for my Destroyer but never inserted it. It's sort of like a 308 adapter for a 30-0-6 chamber. With the adapter you could use inexpensive 9mm surplus and shoot at a lower cost. But even with the 9mm, I would not hot-rod it.
I don't know when they stopped making the Destroyer or how old they are but I would always use caution with these Mini-Mausers. Otherwise, they are fun guns that will effectively handle 9mm Largo pressures and loads, and those are better than the 9mm Luger, so have fun but be careful. This be Mikey.